Helmut Hasse
Helmut Hasse (25 August 1898 – 26 December 1979) was a German mathematician specializing in algebraic number theory, renowned for his foundational work on class field theory, p-adic methods, and the local-global principle for quadratic forms.[1] Born in Kassel to a judge father and a mother of American origin, Hasse studied at the University of Göttingen under influencers like Hilbert and Noether before completing his doctorate in Marburg with Kurt Hensel in 1921.[1] His career advanced rapidly, serving as a lecturer in Kiel from 1922, professor in Halle from 1925, Marburg from 1930, and Göttingen from 1934, where he contributed to rebuilding the mathematics department amid political upheavals.[1] Hasse's key achievements include proving an analogue of the Riemann hypothesis for elliptic curve zeta functions, developing the Hasse invariant for quadratic forms, and authoring the influential textbook Zahlentheorie, which emphasized local methods in number theory.[1] He also edited Crelle's Journal for five decades, shaping the dissemination of mathematical research.[1] During the Nazi era, Hasse exhibited nationalistic leanings, applying for party membership in 1937 to enhance his influence, though rejected due to a remote Jewish ancestor; he opposed direct Nazi interference in mathematics but endorsed certain regime policies, reflecting the ambiguous positions of many academics.[1] Post-war, he faced dismissal from Göttingen by Allied authorities in 1945 but resumed teaching in East Berlin by 1948 and retired from Hamburg in 1966.[1] His rigorous, local approach revolutionized number theory, influencing fields from Diophantine equations to modern algebraic geometry.[1]Biography
Early Life and Education
Helmut Hasse was born on 25 August 1898 in Kassel, in the Province of Hesse-Nassau, German Empire.[1][2] His father, Paul Reinhard Hasse, was a judge, while his mother, Margarete Haße (née Quentin), had been born in Milwaukee, Wisconsin, United States, but relocated to Kassel at the age of five.[1][2] Hasse received his early secondary education at various gymnasiums in the Kassel region. In 1913, following his father's appointment to a senior judicial position, the family moved to Berlin, where Hasse attended the Fichte-Gymnasium for two years.[1][2] To enlist in the Imperial German Navy amid World War I, Hasse took the Notabitur, an expedited secondary school leaving examination.[2] He volunteered for naval service and was later stationed in Kiel. During his final year of service in 1918, he attended mathematics lectures by Otto Toeplitz at the University of Kiel and independently studied number theory from Dirichlet and Dedekind's works.[2] In the 1917–1918 academic year, he was temporarily released from duty to enroll at the University of Berlin, attending courses by Issai Schur, Erhard Schmidt, and Ferdinand Georg Frobenius.[1] Following the war's end, Hasse began formal university studies at the University of Göttingen in December 1918, where he was influenced by lecturers including David Hilbert, Edmund Landau, Erich Hecke, and Emmy Noether.[1][2] In 1920, he transferred to the University of Marburg to work under Kurt Hensel, whose 1913 book on Zahlentheorie had inspired him.[1][2] There, Hasse completed his doctoral dissertation in 1921, titled Über die Darstellbarkeit von Zahlen durch quadratische Formen im Körper der rationalen Zahlen (On the Representability of Numbers by Quadratic Forms in the Field of Rational Numbers), which explored connections between quadratic forms, p-adic numbers, and the local-global principle.[1][2]